fix(core): edge cache not clear when update or delete associated vert…

…ex (#1780)

* Fix the bug when vertex updated, but the edge cache associated with that vertex
   was not updated. Here we simply clear all edge cache when  any vertex changes.
* Add two test case for the fixing

fix #1779

hugegraph-core/src/main/java/com/baidu/hugegraph/backend/cache/CachedGraphTransaction.java

@@ -394,8 +394,13 @@ protected final void commitMutation2Backend(BackendMutation... mutations) {
                 }
             }
 
-            // Update edge cache if any edges change
-            if (edgesInTxSize > 0 && this.enableCacheEdge()) {
+            /*
+             * Update edge cache if any vertex or edge changed
+             * For vertex change, the edges linked with should also be updated
+             * Before we find a more precise strategy, just clear all the edge cache now
+             */
+            boolean invalidEdgesCache = (edgesInTxSize + updates.size() + deletions.size()) > 0;
+            if (invalidEdgesCache && this.enableCacheEdge()) {
                 // TODO: Use a more precise strategy to update the edge cache
                 this.edgesCache.clear();
                 this.notifyChanges(Cache.ACTION_CLEARED, HugeType.EDGE, null);

hugegraph-test/src/main/java/com/baidu/hugegraph/unit/cache/CachedGraphTransactionTest.java

@@ -30,7 +30,9 @@
 import com.baidu.hugegraph.backend.id.Id;
 import com.baidu.hugegraph.backend.id.IdGenerator;
 import com.baidu.hugegraph.schema.VertexLabel;
+import com.baidu.hugegraph.structure.HugeEdge;
 import com.baidu.hugegraph.structure.HugeVertex;
+import com.baidu.hugegraph.structure.HugeVertexProperty;
 import com.baidu.hugegraph.testutil.Assert;
 import com.baidu.hugegraph.testutil.Whitebox;
 import com.baidu.hugegraph.type.HugeType;
@@ -65,14 +67,27 @@ private CachedGraphTransaction cache() {
 
     private HugeVertex newVertex(Id id) {
         HugeGraph graph = this.cache().graph();
+        graph.schema().propertyKey("name").asText()
+             .checkExist(false).create();
         graph.schema().vertexLabel("person")
-                      .idStrategy(IdStrategy.CUSTOMIZE_NUMBER)
-                      .checkExist(false)
-                      .create();
+             .idStrategy(IdStrategy.CUSTOMIZE_NUMBER)
+             .properties("name").nullableKeys("name")
+             .checkExist(false)
+             .create();
         VertexLabel vl = graph.vertexLabel("person");
         return new HugeVertex(graph, id, vl);
     }
 
+    private HugeEdge newEdge(HugeVertex out, HugeVertex in) {
+        HugeGraph graph = this.cache().graph();
+        graph.schema().edgeLabel("person_know_person")
+             .sourceLabel("person")
+             .targetLabel("person")
+             .checkExist(false)
+             .create();
+        return out.addEdge("person_know_person", in);
+    }
+
     @Test
     public void testEventClear() throws Exception {
         CachedGraphTransaction cache = this.cache();
@@ -125,4 +140,83 @@ public void testEventInvalid() throws Exception {
         Assert.assertEquals(2L,
                             Whitebox.invoke(cache, "verticesCache", "size"));
     }
+
+    @Test
+    public void testEdgeCacheClearWhenDeleteVertex() {
+        CachedGraphTransaction cache = this.cache();
+        HugeVertex v1 = this.newVertex(IdGenerator.of(1));
+        HugeVertex v2 = this.newVertex(IdGenerator.of(2));
+        HugeVertex v3 = this.newVertex(IdGenerator.of(3));
+
+        cache.addVertex(v1);
+        cache.addVertex(v2);
+        cache.commit();
+        HugeEdge edge = this.newEdge(v1, v2);
+        cache.addEdge(edge);
+        cache.commit();
+        Assert.assertTrue(cache.queryEdgesByVertex(IdGenerator.of(1)).hasNext());
+        Assert.assertTrue(cache.queryEdgesByVertex(IdGenerator.of(2)).hasNext());
+
+        Assert.assertEquals(2L,
+                            Whitebox.invoke(cache, "edgesCache", "size"));
+        cache.removeVertex(v3);
+        cache.commit();
+        Assert.assertEquals(0L,
+                            Whitebox.invoke(cache, "edgesCache", "size"));
+
+        Assert.assertTrue(cache.queryEdgesByVertex(IdGenerator.of(1)).hasNext());
+        Assert.assertTrue(cache.queryEdgesByVertex(IdGenerator.of(2)).hasNext());
+        Assert.assertEquals(2L,
+                            Whitebox.invoke(cache, "edgesCache", "size"));
+
+        cache.removeVertex(v1);
+        cache.commit();
+
+        Assert.assertEquals(0L,
+                            Whitebox.invoke(cache, "edgesCache", "size"));
+        Assert.assertFalse(cache.queryEdgesByVertex(IdGenerator.of(2)).hasNext());
+    }
+
+    @Test
+    public void testEdgeCacheClearWhenUpdateVertex() {
+        CachedGraphTransaction cache = this.cache();
+        HugeVertex v1 = this.newVertex(IdGenerator.of(1));
+        HugeVertex v2 = this.newVertex(IdGenerator.of(2));
+        HugeVertex v3 = this.newVertex(IdGenerator.of(3));
+
+        cache.addVertex(v1);
+        cache.addVertex(v2);
+        cache.commit();
+        HugeEdge edge = this.newEdge(v1, v2);
+        cache.addEdge(edge);
+        cache.commit();
+        Assert.assertTrue(cache.queryEdgesByVertex(IdGenerator.of(1)).hasNext());
+        Assert.assertTrue(cache.queryEdgesByVertex(IdGenerator.of(2)).hasNext());
+
+        Assert.assertEquals(2L,
+                            Whitebox.invoke(cache, "edgesCache", "size"));
+
+        cache.addVertexProperty(new HugeVertexProperty<>(v3,
+                                                         cache.graph().schema().getPropertyKey("name"),
+                                                         "test-name"));
+        cache.commit();
+        Assert.assertEquals(0L,
+                            Whitebox.invoke(cache, "edgesCache", "size"));
+
+        Assert.assertTrue(cache.queryEdgesByVertex(IdGenerator.of(1)).hasNext());
+        Assert.assertTrue(cache.queryEdgesByVertex(IdGenerator.of(2)).hasNext());
+        Assert.assertEquals(2L,
+                            Whitebox.invoke(cache, "edgesCache", "size"));
+
+        cache.addVertexProperty(new HugeVertexProperty<>(v1,
+                                                         cache.graph().schema().getPropertyKey("name"),
+                                                         "test-name"));
+        cache.commit();
+
+        Assert.assertEquals(0L,
+                            Whitebox.invoke(cache, "edgesCache", "size"));
+        String name = cache.queryEdgesByVertex(IdGenerator.of(1)).next().outVertex()
+                     .value("name");
+        Assert.assertEquals("test-name", name);
+    }
 }